This invention relates to a method for protecting or repairing cementitious substrates such as those made of Portland cement.
Cementitious compositions are widely used in numerous fields. Particularly important compositions include conventional concrete blends which employ Portland cement, a fine aggregate (such as sand), and a coarse aggregate of stone. These materials are used not only to make conventional building structural components, such as beams, columns, walls, and floors, which may be protected from the weather, but also such exposed components as roofs, sills, and foundations. Concrete compositions are also commonly used to make tunnels, tanks, and conduits which may be subjected to virtually constant contact with standing or moving water, or other agents.
Because of its overall characteristics and its economy of use, concrete is a highly preferred construction material; however, it has certain disadvantages. For example, water contact will gradually attack and erode away the interstitial bonding ingredients of the Portland cement, leaving loose aggregate, and thus weakening the structure. The concrete is especially subject to attack by liquids containing acidic components, and thus water that contains acid impurities, such as may be found in sewage drainage conduits or drainage pipes from acid-containing soil, causes accelerated erosion of the concrete structure.
Erosion of the bonding element of the concrete may extend a considerable depth from the outer surface. Thus, the weakness of the concrete structure may be disguised by its external appearance; yet, the weakened structure may virtually crumble or disintegrate under its own weight or from even slight external agitation.
The foregoing deficiencies of the prior art can be eliminated or greatly alleviated in accordance with the present invention.